Two-note solenoid switch mechanism



July 22, 1958 J. w. CHRISTY ETAL 2,844,680

TWO-NOTE SOLENOID SWITCH MECHANISM Filed Jan. 18, 1957 5 Sheets-Sheet 3 2 11 41 -1e ZZ I2 a r I 77X 76 $5 a V 75 W 3 4 10 INV N 0R8.

BY Wl w A TTOENEXS.

United States Patent D M TWO-NOTE SOLENOID SWITCH MECHANISM James W. Christy, Cincinnati, and Joseph McEvoy, Ba-

tavia, Ohio, assignors to Nutone, Inc., a corporation of New York Application January 18, 1957, Serial No. 634,847

12Claims. (Cl. 200-87) This invention relates to solenoid-operated signals, such as door chimes, utilizing two solenoids to create a two-note signal and utilizing one of the solenoids individually to create a single note signal. The invention isidirected particularly to a switching mechanism which is actuated by one of the solenoids to energize a second .solenoid, thereby to produce the two-note signal in response to energization of the first solenoid by a push button or the like.

A solenoid actuated signal system providing a single and two-note signal of this type is disclosed in the copending application of James W. Christy et al. .filed on October 6, 1954, Serial No. 460,554, .nowPatent No. 2,799,016, issued July 9,1957, to which attention is invited. According to the co-pending application, one of the solenoids, which is termed the primary solenoid, is connected to a two-note push button, such that its plunger .is advanced electro-magnetically under high velocity when the push button is depressed, the plunger being retracted at a lower velocity by a compression spring when the push button is released to deenergize the solenoid. The plunger of the primary solenoid carries a moving contact element which wipes across a stationary contact means to create an electrical impulseduring the high velocity power stroke of the plunger and also during its low velocity retracting stroke. A secondary solenoid is electrically connected to the contact means, and although an electrical impulse is sent to the secondary solenoid during the high velocity power stroke, the impulse is too brief to overcome the electrical and mechanical lag of the secondary solenoid; however, during the return strokeat low velocity, the impulse'has suflicient duration to energize the secondary solenoid. Accordingly, the primary solenoid sounds its signal when the two-note push button is depressed and the secondary solenoid is energized momentarily to sound the .second signal during the retracting motion of the primary plunger after the push button is released.

The present invention contemplates a signal system of the same character; however, the present structure utilizes a mechanical switching mechanism in connection with the primary solenoid, so arranged that an electrical impulse is sent to the secondarysolenoid onlyduring the retracting stroke of the primary solenoid. Therefore, the present structure provides the same advantages as the prior structure, but utilizes a-mechanical, one-way switch closing principle instead of depending upon the low velocity return motion of the primary solenoid to energize the secondary solenoid.

In general, thepresent switchingrnechanism comprises a flapper or one-way switch closer hingedly connected to the plunger of the primary solenoid and coacting with a set of stationary contacts which are electrically connected to the secondary solenoid. The stationary contacts are normally open and the lower contact or actuating plate resides at a given plane above the primary plunger. In the normal position of theprimarytplunger, with'the solenoid deenergize'd, theflapper residesin' an 2,844,680 Patented July 2 2, 1958 the contact actuating plate during .the forward stroke without actuating it. However, when the plunger strikes its tone bar, the impactfforces act upon the flapper to shift it to an active position. Upon deenergization of the primary solenoid, its plunger is propelled by a compression spring back to its normal retracted position; since the flapper is now in =its-elevated active position, it wipes across the actuating plate and earns it upwardly into engagement with its companion contact so --as to complete the electrical circuit to the secondary solenoid. Uponireachin'g its fully retracted position after passing the actuating plate, the primary plunger engagesastop element, whereupon impact forces again act upon the flapper to shift-it \back to itsinactive position ready for the next cycle of operation.

One of :the primary objectives of the invention has been to provide positiveoperation of the secondary solenoid during the retracting strokeof'the primary plunger, such that theoperationis 'notelfectedby variable'factors in the operation of the primarysolenoid. This is brought about by the one-way operation of the flapper with respect .to vthe .actuating plate, whereby the stationary contact elementsmemain .open during the power stroke and are closed in a positive manner during 'theretracting stroke by the flappen. Moreover, the flapper and stationary contact .elementsprovidea signal impulse of .controlled durationandintensity which overcomes the mechanical andtelectrical lag.of..the secondarysolenoid.

Another objective has been to improve the operation of the primary plunger by reducing to a minimum any forces which tend totimpede its forward striking motion. According to the .presentstructure, the primary plunger is substantially .free of resistance during its power stroke, except for the biasing effect .of the compression spring, by virtue of the one-way operationof the flapper. Therefore, practically .all of the excess energy of the plunger during the power stroke is stored in the spring and is available to-close the contacts during the spring retraction stroke of the plunger.

A further objective has been .to provide a switching mechanism which creates .an .improved circuit closing action and which operates at maximum efiiciencyover a prolonged service period with very little wear. For this purpose, the actuating .plate, which is.engaged by the iflapper'has asubstantial lengthin the direction of longitudinal flapper movement, causing theactuating plate to be shifted upwardly, while at thesame time, a rolling action is imparted to it. The upper contact element includes a partially spherical. contact dimple which projects downwardly toward the flatsurface ofthe actuating plate to complete the circuit. "Duringthe upward rollingmotion of the actuatingplate, .thedimple provides a substantially single-point contact with the actuating plate, thus concentrating the .contact pressure; on the other hand, the rolling motion of. theflatactuating; plate against the spherical dimple.surfacedistributesthe wearing'efiect lineally along the meeting .surfacesof the dimple and plate while maintaining .the single point contact.

Various other features and advantages of the-present invention will .be'morefully apparent to those skilled in the artfrom the .followingdetailed description takenin conjunction with thetdrawings.

In the drawings:

Figure 1 is a front view of a chime signal assembly embodying the present invention.

Figure 2 is an enlarged sectional view taken online 2'2 of Figure l, detailing the construction of the switch ing mechanism of the primary solenoid.

Figure 3 is a fragmentary sectional view taken on line 3-3 of'Figure'L'further detailing the primary solenoid andits'switchingmechanism.

Figure 4 is a fragmentary top plan view of the switching mechanism as projected from Figure 2.

Figure 5 is an enlarged fragmentary sectional view taken from Figure 3, detailing the switch-actuating flapper and its connection with the rearward end of the primary plunger. The flapper is shown in its inactive position corresponding to that shown in Figure 3.

Figure 6 is an enlarged fragmentary view similar to Figure 5, showing the flapper in its active or elevated position.

Figure 7 is an enlarged cross sectional view taken along line 7-7 of Figure 5, further detailing the flapper construction.

Figures 8 to 11 inclusive are diagrammatic views showing the operation of the flapper and contact elements during the forward and retracting strokes of the primary solenoid.

Figure 12 is a diagram of the electrical circuit, showing the action of the primary solenoid when the two-note signal button is depressed.

Figure 13 is a diagrammatic view similar to Figure 12, showing the circuit to the secondary solenoid completed by the primary solenoid when the two-note push button is released to allow the primary solenoid to retract.

General arrangement Referring to Figures 1 and 2, the present structure comprises in general a primary solenoid indicated at and a secondary solenoid indicated at 11, the two solenoids being mounted upon a panel 12. The panel is enclosed within a housing 13 formed of sheet metal having a cover 14 which is partially broken away to illustrate the arrangement of the components. The two tone bars 15 and 16 are mounted within the housing and reside adjacent the ends of the solenoids in respective positions to be struck by the solenoid plungers. The tone bars are mounted upon a common resonator tube 17 having an intermediate wall 18 which divides the tube into two resonator sections. The side wall 20 of the tube adjacent the tone bars includes openings 21--21, providing communication between the tone bars and resonator sections.

The tone bars and resonator sections are pitched musically to produce two distinctive notes when the tone bars are sounded separately and to produce a harmonious twonote chord effect when the tone bars are sounded in sequence. When the two-note push button is depressed, as explained later, the primary solenoid 10 is energized first to strike its tone bar, and upon the return stroke of the primary plunger, its switching mechanism energizes the secondary solenoid 11 to create the second note in sequence. When the single note push button is depressed, the secondary plunger is energized independently, thus creating the single note chime signal.

In order to conserve space, the resonator tube 17 in the present disclosure is square in cross section and comprises a right angular sheet metal piece forming the side wall 20 and a front wall 22, the remaining two sides being constituted by the side and back wall of housing 13. The tone bars 15 and 16 are mouned upon the side wall 20 by pairs of rivets 23 which pass through the tone bars, the tone bars being cushioned by soft rubber grommets 24 surrounding the rivets. The grommets are spaced outwardly from the wall 20 by spacers 25, the rivets passing through the spacers and through wall 20.

Panel 12, which supports the two solenoids, is detachably mounted within housing 13 by nuts 26 which are threaded on studs projecting outwardly from the rear wall 27 of housing 13. To provide clearance for the electric wiring which interconnects the two solenoids, and which passes outwardly to the push buttons and transformers, as explained later, the panel 12 is spaced outwardly from the rear wall 27 by spacers (not shown) which may be placed upon the studs between the panel and rear wall. As shown in Figure 2, panel 12 includes an opening 28 behind each solenoid, such that the wiring may pass from 4 the solenoids to the space between the panel and rear wall, the external wiring for the push buttons and transformer passing outwardly through an opening in the housing (not shown).

Solenoid structure In the present disclosure, the two solenoids 10 and 11 are identical in construction except that the primary solenoid 10 is provided with a switch housing 30 which encloses the switching mechanism of the present invention. Therefore, the following detailed description of solenoid 10 applies to both, the same reference numbers being applied to corresponding parts of both solenoids. Referring to Figures 2 and 3, which show the construction of the primary solenoid 10, a solenoid tube formed of brass or similar non-magnetic material, is indicated at 31, with a solenoid plunger 32 slidably sustained Within the tube. The plunger is fabricated from a magnetic material such as iron or steel, and to reduce friction, each plunger includes a narrow bearing bead 33 formed on its opposite ends, the beads slidably interfitting the tube, while the body of the plunger is of smaller diameter. In the normal position (Figure 3), with the solenoid dcenergized, the forward end of the plunger extends partially within the solenoid coil 34, which is wound upon the end portion of the solenoid tube. A sleeve 35, formed of elec trical insulating material, is interposed between the coil and tube. Each solenoid coil 34 is enclosed by a coil housing 36, preferably in the form of sheet metal stamping which includes a mounting flange 37 secured to panel 12 by screws 38 (Figure 2).

The forward end of each solenoid plunger includes an outwardly projecting stem 40 of a non-magnetic material, such as a fiber or plastic composition, which may be pressed into a hole drilled axially into the end of the plunger. The stem impinges against the related tone bar 15 or 16 to sound the chime signal upon energization of the solenoid coil. In its deenergized position, as shown in Figure 3, the plunger and its stem are maintained in the retracted position by a compression spring 41 having one end seated against the plunger and its opposite end seated against a retainer cap 42, which is pressed upon the outer end of the solenoid tube. The retainer cap comprises a sheet metal stamping and includes a central opening 43 which provides clearance for stem 40.

The structure so far described applies to both solenoids 10 and 11 except that the secondary solenoid 11 includes a rubber cap 44 at its rearward end, which as shown in Figure 12, acts as a stop for the solenoid plunger 32, in its retracted position as biased by compression spring 41. The primary solenoid 10, includes a stop means serving the same purpose and consisting of a soft pad 45 located in the switch housing 30 as explained later.

Both solenoids have the same principle of operation as described later in detail with reference to the primary solenoids. It will be understood at this point, with reference to Figure 9', that upon energization of coil 34, the plunger is propelled electro-magnetically at high velocity toward its tone bar, the magnetic flux of the coil being sufilcient to overcome the resistance of spring 41. Upon striking the tone bar, the plunger immediately retracts, such that the end of the stem is spaced from the tone bar to provide an air gap. It remains in this position so long as the coil is energized. The plunger is shifted to its retracted position by the energy stored in spring 41, when the coil is deenergized (Figures 10 and 11).

Switching mechanism As noted earlier, the switching mechanism which actuates the secondary solenoid 11 in response to operation of the primary solenoid 10, is enclosed within the switch housing 30 of the primary solenoid. The switch housing is fabricated from an insulating material and comprises a base 46 and a detachable cover 47 secured upon the base by screws as described later. The base and covers preferably are molded from a plastic composition and are similar to the parts disclosedin the co-pending application. The stop pad 45 is carried by a depending portion 48 of the cover (Figure 3).

The base 46 of the switch housing is bored longitudinally to fit snugly over the solenoid tube 31 and the tube includes a tang 50 slit from its inner end and bent downwardly into a slot 51 formed in the end of the base .(Figure 3).

The opposite end of base 46 contacts coil housing 36, such that the switch housing is secured longitudinally on the tube between the housing and tang. The slot 51, in which the tang is seated, acts as a key to lock the switch housing against rotary motion with respect to the tube. The cover 47 of the switch housing includes a side wall 52 and forms a chamber 53 above the solenoid tube (Figure 2). The cover is secured in position by screws 54 threaded into flanges 55 which extend outwardly along opposite sides of the base 46.

The switching mechanism of the present invention resides within the chamber 53 and comprises a flapper or one-way switch closer indicated at 56 which coacts with a stationary switch assembly indicated generally at 57, mounted within chamber 53. The flapper is connected to the rearward end of the primary solenoid plunger 32 for swinging motion, being loosely carried upon a stud 58 formed of non-magnetic material.

Flapper 56 preferably is in the form of a one-piece .staping formed of non-magnetic sheet metal such as brass or the like. As viewed in Figures 5-7, the flapper is in the form of an upstanding finger or lug having a ring 60 loosely encircling the stud 58 and confined loosely between the end of plunger 32 and the head 61 of the stud. It is mounted on the plunger by slipping the ring 60 upon .the stud, then mounting the stud in a bore formed in the end of the plunger, the stud preferably being pressed into the bore. As viewed from the side (Figure 5), the lower .half of ring 60 is bent rearwardly as at 62, and resides at .an angle to the plane of the flapper. This configuration .allows the flapper to assume the inactive, rearwardly inclined position of Figures 3 and 5, the head 61 being generally cone-shaped to accommodate the flapper. During the forward or power stroke of the solenoid, the flapper remains in the inactive position; it assumes the elevated or active position of Figure 6 during return motion of the plunger. This action provides the one-way switch closing action, as explained later in detail.

To provide the longitudinal motion of the flapper 56 with the plunger, a longitudinal clearance slot 63 is formed in the upper portion of solenoid tube 31 (Figures 7 and 8).

A matching slot 64 is formed in the upper portion of the base (Figure 2). The longitudinal slot 63 is sufliciently wider than the flapper to provide clearance for unrestricted longitudinal motion of the flapper. As shown in Figure 5, the upper end of the flapper projects through the slot; accordingly, the flapper is slidably keyed by the slot in its upstanding position. v

The stationary switch assembly, indicated previously at 57, comprises a lower contact strip and an upper contact strip both formed of thin, flexible sheet metal. As viewed from above (Figure 4), the contact strips are generally Z-shaped, each consisting of a fixed mounting plate 65, and a yieldable arm 66, the contact means being joined to the outer ends of the yieldable arm as explained below. The mounting plates 65 are secured in spaced relation, one above another between insulating strips 67, the lowermost insulating strip resting upon the top surface of the base to space the lower contact stripiabove the base and solenoid tube (Figure 2).

Both yieldable arms 66 overhang the slot 63 in cantilever fashion, their mounting plates being secured in position upon the base by screws 68 passing through the mounting plates and insulating strips into threaded engagement with the base. Suitable insulating means may surround the screws to insulate the mounting plates from one another, such that the circuit through the strips normally is open. It will be noted in Figure '4, that the wardly projecting tang 70, the two .tangs being spaced apart from one another and providing electrical terminals for a pair of wires which are soldered as at 71 to the respective terminals. These wires are indicated in the electrical circuit as described later and energize secondary solenoid when the contact strips are actuated by the flapper.

As viewed from the side (Figure :3), the contact head 71 of the lower arm 66 forms an actuating plate which includes an upwardly inclined'skid 72 at its opposite ends. It will be seen that the actuating; plate 71 extendsparallel with the longitudinal slot 63 in a normal plane above the tube and that the upper contact head 73 is provided with a partially spherical contact dimple 74 whichprojects downwardly toward the actuating plate between its upwardly inclinedskids 72. -In-the normal open position of the parts (Figure 8), the dimple is spaced as at 75 above the flat surface of the actuatingplate, such that the circuit is open. The actuating plate 71 isshifted upwardly intocontact with dimple 74, as explained briefly below.

It will'be seen in Figure 5, that the angular portion 62 of the flapper ring engages the lower portion of stud 58, while the flapper 56 rests against the conical head 61 of the stud to support the flapper in its inactive rearwardly inclined position. In other words, the ring and flapper interfit the stud audits head in such a way that the flapper is sustained bydirect abutment at 'two points only; therefore, the flapper is free to pivot in a plane parallel with the plunger. In this position, theflapper'is free to pass beneath the actuating .plate 71 (Figure 8).

To provide the one-way operation of the switching mechanism, the flapper is shifted-to its second position shown in Figure 6 by impactforce when the plunger strikes the tone bar at the forward end of its strike. It will be seen in Figure 5, that the mass of the flapper, when in its inactive position, resides .above itsring which provides the pivot-point. Accordingly, at the point ofimpact, the momentum force stored in the flapper acts along lines parallel with the plunger axis and thereby swings the flapper forwardly aboutits pivot point.

Upon swinging forwardly to its active position (Figure 6) the flapper assumes a position .in whichit'is .inclined slightly in the forward direction. It is supported vin this position by engagement of the angular ring portion 62 with the head 61, the upper portion-ofthe ring and'flapper resting against the end of the ,plunger. vIt will be noted that .in this second'oractive position, :the upper end of the'flapper has been shifted above thenormalplane of the switch actuating plate 71 (Figure 9). 3

During the return stroke (Figures 9-11), with the flapper thrown to its active position, the upper end of the flapper cams against the actuating plate and forces it upwardly into contact with dimple .74 to close the circuit. It will be noted that during the return motion, with the flapper in contact with the plate, the flapper is wedged 011 its stud 58 in the :elevated position. The camming motion of the flapper against the forward skid 72 and across the flat surface of the plate 71 is accompanied with a rocking action as described in detail later. After passing beyond the rearward skid 72, the rearward end of the plunger strikes the :cushion 45, thereby throwing the flapper back to .its normal inactive position.

Electrical circuit and operatiom is completed to the coil of the primary solenoid '10 by way of line 84; accordingly, the primary solenoid is energlzed when push button 82 is depressed.

The circuit to the secondary solenoid 11 is completed from line 84 and branch line 85 to the actuating plate 71 and from contact strip 73 and line 86 to the coil 34 of solenoid 11. As noted earlier, the dimple 74 of the upper contact strip normally is spaced from the actuating plate 71, such that the circuit by way of lines 85 and 86 to the secondary solenoid normally is open.

When the two-note push button 82 is depressed therefore, the primary plunger 32 is propelled at high velocity toward its tone bar 15, as shown by the arrow in Figure 12. As noted earlier, the magnetic force of coil 34 is sufiicient to overcome the resistance of the compression spring 41, causing the stem 40 to strike its tone bar under momentum as shown in broken lines in Figures 9 and 12. As noted earlier, the resistance of spring 41 is slightly greater than the magnetic force, causing the solenoid plunger to immediately retract to a position in which the magnetic force balances the compression force stored in the spring. This position is shown in full lines in Figures 9 and 12, the plunger remaining in this position until the coil is again deenergized, the air gap being indicated 79.

As noted earlier, during the forward motion of the plunger under magnetic force, the flapper (in its inactive position) passes beneath the actuating plate 71 without closing the contacts (Figure 8); hence, the secondary solenoid is not energized during the forward plunger motion. When the plunger strikes its tone bar, the impact swings the flapper upwardly by momentum to the position shown in broken lines in Figure 9, in which it locks itself, subsequently to cam the actuating plate upwardly.

It will be noted at this point, that the flapper does not create any frictional resistance during the forward plunger motion. Accordingly, the striking action of the plunger is improved and its switch-closing effort is strengthened by being concentrated in one stroke.

When the plunger assumes its balanced position (with the winding energized), the flapper is carried to the position shown in full lines in Figure 9. It will be noted that in the second position, the upper end of the flapper is above the plane of actuating plate 71 and adjacent the forward skid 72; hence, it cannot drop rearwardly to its inactive position.

When the push button 82 is released and the primary solenoid is deenergized (Figure 10) the compression spring 41 returns the plunger to its normal position and the upper end of the flapper cams against the inclined skid 72 and thus forces the forward end of plate 71 upwardly. This motion is accompanied with a rocking motion, indicated by the arrows, with plate 71 in contact with dimple 74, thus closing the circuit. As the flapper continues its rearward motion, the plate 71 rocks about the dimple in the opposite direction (Figure 11), then the flapper clears the rearward skid. At this point, the parts assume the normal position shown in Figure 3.

Referring to Figure 13, it will be noted that when the flapper first cams plate 71 into contact with the dimple 74, a circuit is completed by way of line 85 through the contacts 71 and 73 and line 86 to the secondary solenoid winding. The rocking motion as the flapper cams across the actuating plate 71 provides an electrical impulse of suflicient duration to allow the secondary solenoid coil to build up to full strength, causing the secondary plunger to strike its tone bar 16 (Figure 13) and then to return to its retracted position after the flapper retracts beyond the rearward skid of actuating plate 71.

It will be observed at this point, that the spherical dimple provides substantially a single point contact with. the flat surface of the actuating plate; therefore, the actuating pressure is concentrated to create maximum electrical conductivity. On the other hand, the rolling action distributes wear about the dimple surface while maintaining the single point contact. Accordingly, a

positive electrical contact is assured even after prolonged service of the switching mechanism.

When the single-note push button 87 is depressed to provide the second signal, the circuit is completed from lines 84, and 88, through the push button, and by line 86 to the coil. The opposite side of the coil is energized by the transformer line 83. This circuit bypasses the primary solenoid 10 and causes the secondary solenoid 11 to sound a single note. The two distinct notes sounded by push button 82 and single note push button 87 thus indicate clearly which call is to be answered.

Having described our invention, we claim:

1. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary solenoid and a secondary solenoid, said primary solenoid having a shiftable plunger, a solenoid coil for propelling the plunger forwardly in a power stroke, and yieldable means normally urging said plunger to retracted position; said switching mechanism comprising, a stationary electrical contact device, a movable contact-actuating element pivotally connected to said plunger for movement therewith in a path relative to the said contact device, said element having a swinging portion and being shiftable in response to impact forces relative to the plunger to an active or inactive position and being effective to actuate said contact device when in said active position, the actuating element residing in said inactive position during the forward power stroke of the plunger upon energization of said coil, and

shifting to an active position in response to impact force at the limit of said power stroke, the contact-actuating element remaining in said active position during motion of the plunger toward said retracted position by said yieldable means upon deenergization of said coil, said actuating element thereby actuating the contact device during the said retracting stroke, said contact device making and breaking an electrical circuit upon being actuated and thereby adapted to be electrically connected to a secondary solenoid to energize the same momentarily in re sponse to actuation of the contact device by said actuating element, said contact-actuating clement shifting to said inactive position in response to impact force at the limit of the retracting stroke of said plunger.

2. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary and a secondary solenoid, said primary solenoid having a solenoid tube, a shiftable plunger in said tube, a solenoid coil for propelling the plunger forwardly in a power stroke, and spring means normally urging said plunger to a retracted position; said switching mechanism comprising, a stationary electrical contact device mounted along the path of travel of said plunger, a flapper element shiftably connected to said plunger, said flapper element being shiftable to an active or inactive position with respect to the plunger, said flapper element residing in an inactive position when said plunger is in the said retracted position, said flapper element advancing relative to said contact device while in said inactive position during the forward power stroke of the plunger, said flapper element shifting to said active position in response to the power stroke of the plunger, said spring means shifting the plunger toward said retracted position upon deenergiza tion of said coil with the flapper element in said active position, said flapper element engaging said contact device and actuating the same during said retracting motion, said contact device making and breaking an electrical circuit upon being actuated by the flapper element, said contact device adapted to be electrically connected to a secondary solenoid to energize the same momentarily in response to actuation of the contact device by said flapper element.

3. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary and a secondary solenoid, said primary solenoid having a shiftable plunger, a solenoid coil for propelling the plunger forwardly in a power stroke, and spring means normally urging said plunger to a retracted position; said switching mechanism compris- 'gsaaeso ing, a stationary electrical contact device mounted relative to said plunger, a one-way switch actuating element pivotably connected to said plunger for movement therewith, said switch actuating element having a swinging portion and being shiftable in response to impactforces to an active or inactive position, said elementresiding in an inactive positionand moving relative to the contact device in a path spaced from the contact device during the power stroke of the plunger upon energization of said coil, said one-way switch actuating element shifting to an active position in response to impact force at the limit of the said power stroke of the plunger, said spring means shifting the plunger toward said 'retracted'position upon deenergization of said coil, "said one-wayswitch actuating element moving in a'path intercepting the contact device during said retracting motion and thereby actuating the contact device, the contact device making and breaking an electrical circuit upon actuation by said one-way actuating element, said contact device thereby adapted to energize the secondary solenoid momentarily in response to actuation by saidactuatingelement, said one-way switch actuating element shifting to said inactiverposition by impact force attheslimit of said retracting motion of the plunger.

-4. A solenoid-actuated switchingmechanism for a'sole- 'noid apparatus having a primary solenoid and a secondary solenoid, said primary solenoid having a.:shiftable plunger, a solenoid coil for propelling the plunger forwardly in a power stroke, and yieldable means normally biasing said plunger to a retracted position; said switchingmechanism comprising, a stationary contact .device mounted relative to said plunger, a one-way contact actuating element hingedly connected to said plunger for movement therewith, said actuating elementpivoting to an inactive or active position withresp'ect to said plunger in response to impactforces, said actuating element advancing in a longitudinal path spaced from the'contact device when in inactive position .and retracting in a second longitudinal .path intercepting the contact device when in active position, the actuating element advancing longitudinally while in said inactive position duringthe forward power stroke of the plunger upon energization of said coil, said element pivotingto said active position in response to impact force at a forward limit of saidpower stroke, said yieldable means shifting the plungerlin a retracting stroke upon deenergization of said coil, whereby said switch actuating element retracts with the plunger while in said second longitudinal path intercepting the stationary contact device, the said actuating element engaging and actuating thetcontact device during ;saidretracting stroke, said contact device adapted to be electrically connected to a secondary solenoid to energize the same momentarily upon engagementby'said switch actuating element, said one-way contact'actuating device shifting in response to impact force to said inactive position at the limit of the retracting stroke of the plunger.

5. A solenoid-actuated switching mechanism'for a solenoid apparatus having a primary solenoid and a secondary solenoid, said primary solenoid having a solenoid tube, a shiftable plunger in'said tube, a solenoid coil for propelling the plunger through a power'stroke, and biasing means normally urging said plunger to a retracted position; said switching mechanism comprising, a base element mounted on the solenoid tube, an upper and lower yieldable contact strip, said contact strips being spaced apart and having respective outer-portions'rnounted on said base element, said contact strips electrically insulated from one another, the lower contact strip including an actuating plate residing adjacent said solenoid tube, a flapper element hingedly connected to the solenoid plunger and shiftable to an active or inactiveposition, said flapper element normally residing in an inactive position, said solenoid tube including a longitudinal passageway, said'flapper element projecting through said lon- 'gitudinal passageway, said fiapperelement advancing in during the forward power stroke of the plunger a path spaced from said actuating plate while in said inactive position during the power stroke of the plunger upon energization of the solenoid coil, said flapper shifting to said active position under momentum .force at the limit of said power stroke, said biasing means urging the plunger and flapper element through a retracting stroke upon deenergization of the solenoid coil, said flapper element retracting with the plunger along a second path which intercepts said actuating plate, thereby urging the plate and yieldable arm thereof outwardly into contact with the upper contact strip, said contact strips adapted to be electrically connected to a secondary solenoidto energize the same momentarily in response to the retracting stroke of the primary solenoid plunger.

6. A solenoid-actuated switching mechanism for asolenoid apparatus having a primary and a secondary solenoid, said primary solenoid having a shiftable plunger, a solenoid coil for propelling the plunger in a power stroke, and biasing means normally urging said plunger to aretracted position, said switching mechanism comprising, a flapper element hingedly connected to the solenoid plunger for movement therewith, said flapper element pivoting relative to the plunger to an active or inactive position, said flapper element normally residing'in said inactive position and travelling in a longitudinal inactive path during the forward power stroke of the plunger upon energization of said coil, said flapper element pivoting to said active position under momentum force at a forward limit of plunger travel, said biasing means shifting the plunger in a retracting stroke upon deenergization of said coil, said flapper element travelling in an active longitudinal path during said retracting stroke, a pair of superposed yieldable contact strips mounted in stationary position relative to said plunger, said contact strips being spaced apart and electrically insulated from one another, the end portion of one of said yieldable contact strips having an actuating plate residing in a plane spaced outwardly from the inactive longitudinal path of travel of the flapper element and inwardly of the active longitudinal plane thereof, the opposite ends of said actuating plate having outwardly inclined skid portions extending beyond said active longitudinal path, saidfiapper element camming across said skid and plate and'forcing the plate outwardly during travel in said active longitudinal pat said contact strips having contact elements which make and break an electrical circuit upon the outward motion of the actuating plate, said contact strips adapted to be electrically connected to a secondary solenoid to energize the same momentarily upon actuation of the contact strips.

7. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary solenoid and a secondary solenoid, said primary solenoid having a shiftable plunger, a solenoid coil for propelling the plunger forwardly in a power stroke, and biasing means normally urging said plunger to a' retracted position; said switching mechanism comprising, a stationary switch device mounted relative to said plunger, a one-way switch actuating element hingedly connected to said plunger for movement therewith in a longitudinal. path with respect to the switch device, said actuating element pivoting to an inactive or active position with respect to said plunger in response to momentum force, astop element mounted in the path of motion of said plunger and arresting the plunger in said retracted position, said actuating element advancing along a first longitudinal path while in said retracted position upon energization of said coil, said longitudinal path of motion extending from one side to and beyond the opposite side of said switch :device, said actuating element passing in spaced relation to the switch device during motion along said first longitudinal path in said retracted position, said element pivoting to an activeposition under momentum force at a forwardlimit of said power stroke, saidbiasing means'shiftingthe 'plungerin a retracting stroke upon deenergization of said coil with said actuating element residing in said active position, said actuating device engaging and actuating the switch device during said retracting stroke and thereafter passing rearwardly beyond the switch device, said plunger striking said stop element at the limit of said retracting stroke, said actuating element thereupon pivoting under momentum force to said inactive position, said switch device making and breaking an electrical circuit upon being actuated by said element, said switch device adapted to be electrically connected to a secondary solenoid to energize the same momentarily upon actuation of the switch device by said actuating element.

8. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary and a secondary solenoid, said primary solenoid having a solenoid tube, a shiftable plunger in said tube, a coil for propelling the plunger in a power stroke, and biasing means normally urging said plunger to a retracted position; said switching mechanism comprising, a base mounted upon the tube of the primary solenoid, a pair of contact elements, secured to said base and including yieldable arms spaced apart and electrically insulated from one another, one of said arms projecting in cantilever fashion toward the solenoid tube and including an actuating plate at the outer end thereof, the other of said contact arms including a contact dimple projecting toward the surface of said plate and spaced therefrom, a flapper hingedly connected to said plunger and movable longitudinally therewith, said solenoid tube having a longitudinal passageway, said flapper element projecting outwardly through said passageway, said flapper element normally residing in a rearwardly inclined inactive positon, the flapper element travelling in an inactive longitudinal path during the forward power stroke of the plunger upon energizaiton of said coil, said flapper element pivoting to an active forwardly inclined position by momentum force at a limit of said power stroke, said biasing means shifting said plunger rearwardly in a retracting stroke upon deenergization of said coil, said flapper element resting against a second portion of the plunger in said active forwardly inclined position during said retracting stroke and travelling in an active longitudinal path which is spaced outwardly from said inactive path, said actuating plate having an inclined cam surface residing adjacent said longitudinal passageway at a mid-point along the longitudinal path of travel of said flapper element, said inclined cam surface passing through said active path of travel, whereby the flapper element passes in spaced relation to the cam surface during said power stroke and earns across said surface during said retracting stroke, said actuating plate being sprung outwardly into contact with said dimple by said flapper element, said contact elements adapted to be electrically connected to a secondary solenoid to energize the same momentarily upon actuation of said plate by the flapper element.

9. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary solenoid and one or more secondary solenoids which are energized in response to operation of the primary solenoid; said switching apparatus comprising, a primary solenoid having a solenoid tube, a shiftable plunger slidably sustained in said tube, biasing means normally urging said plunger rearwardly to a retracted position, a base element mounted upon the solenoid tube, a flapper element pivotally connected to said plunger for movement therewith, said solenoid tube having a longitudinal passageway therein, said flapper element projecting outwardly through said longitudinal passageway, said flapper element normally residing in a rearwardly inclined inactive position resting against a portion of the plunger, the flapper element travelling along an inactive longitudinal path during the forward power stroke of the plunger upon energization of said primary solenoid, said flapper element pivoting to an active forwardly inclined position by momentum force at a limit of said power stroke, said biasing means shifting said plunger rearwardly in a retracting stroke upon deenergization of said primary solenoid, said flapper element resting against a second portion of the plunger in said active forwardly inclined position during said retracting stroke and travelling along an active longitudinal path which is spaced outwardly from said inactive path, an electrical contact device mounted on said base element, said contact device including a yieldable actuating element having an inclined cam surface residing adjacent said longitudinal passageway at an intermediate point along the longitudinal path of travel of said flapper element, said inclined cam surface passing through said active path of travel of the flapper element, whereby the flapper element passes in spaced relation to the cam surface during said power stroke and cams across said surface during said retracting stroke to shift the yieldable actuating element outwardly, said contact device including contact elements which close upon outward motion of said actuating element, said contact elements adapted to be electrically connected to one or more secondary solenoids to energize the same momentarily upon actuation of the actuating element by the flapper element.

10. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary solenoid and one or more secondary solenoids which are energized in response to operation of the primary solenoid; said switching apparatus comprising, a primary solenoid having a solenoid tube, a shiftable plunger slidably sustained in said tube, biasing means normally urging said plunger rearwardly to a retracted position, a base element mounted upon the solenoid tube, a flapper element pivotally connected to said plunger for movement therewith, said solenoid tube having a longitudinal passageway therein, said flapper element projecting outwardly through said longitudinal passageway, said flapper element normally residing in a rearwardly inclined inactive position resting against a portion of the plunger, the flapper element travelling along an inactive longitudinal path during the forward power stroke of the plunger upon energization of the primary solenoid said flapper element pivoting to an active forwardly inclined position at a limit of said power stroke, said biasing means shifting said plunger rearwardly in a retracting stroke upon deenergization of said primary solenoid, said flapper element resting against a second portion of the plunger in said active forwardly inclined position during said retracting stroke and travelling along an active longitudinal path which is spaced outwardly from said inactive path, a yieldable arm mounted on said base element and having an actuating plate residing at an intermediate point along the said longitudinal path of travel, said plate residing in a plane inwardly of said active path of travel and having skid portions rising outwardly beyond said active path, a contact element mounted on the base element, said contact element including a generally spherical dimple projecting toward the actuating plate and normally spaced therefrom, said yieldable arm adapting the actuating plate to shift outwardly and to rock in said longitudinal path, said flapper element, during movement along said active path, progressively camming across said skid portions and plate and rocking the plate outwardly into contact with said dimple, thereby creating a rolling line contact therebetween, said plate shifting to said normally open position after passage of said flapper to said rearward retracted position, said actuating plate and contact element adapted to be electrically connected to one or more secondary solenoids to energize the same momentarily upon actuation of said plate by the flapper element.

11. A solenoid-actuated switching mechanism for a solenoid apparatus having a primary solenoid and .one or more secondary solenoids which are energized in re- 13 sponse to operation of the primary solenoid; said switching apparatus comprising a primary solenoid having a solenoid tube, a shiftable plunger slidably sustained in said tube, biasing means normally urging said plunger rearwardly to a retracted position, said plunger having a neck portion at the rearward end thereof which is delineated by a pair of spaced shoulders, a flapper having a ring portion loosely embracing said neck portion for movement with the plunger, said solenoid tube having a longitudinal passageway therein, said flapper projecting outwardly through said longitudinal passage and the ring portion providing pivotal motion of the flapper, said flapper normally residing in a rearwardly inclined inactive position resting against one shoulder of said neck portion, the flapper traveling in an inactive longitudinal path during the forward power stroke of the plunger upon energization of said primary solenoid, said flapper element pivoting to an active position by momentum force at a limit of said power stroke, said biasing means shifting said plunger rearwardly in a retracting stroke upon deenergization of said primary plunger, said flapper element resting against the second of said shoulders in said forwardly inclined active position, the flapper in said retracting stroke travelling in a longitudinal path which is spaced outwardly from said inactive path, a normally open contact device mounted in stationary position relative to the solenoid tube, said contact device including a yieldable actuating member residing at an intermediate point along the longitudinal path of travel of said flapper, said actuating member having an inclined cam surface residing outwardly of said inactive path and passing at an angle inwardly and outwardly through the said active longitudinal path of travel, whereby the flapper passes in spaced relation to said cam surface, during said power stroke of the plunger, the flapper camming across said surface and shifting the actuating member outwardly during said retracting stroke, said contact device including contact elements which close upon shifting of said actuating member, said contact device adapted to be electrically connected to one or more secondary solenoids to energize the same momentarily upon actuation of said memher by the flapper.

12. A solenoidactuated switching mechanism for a solenoid apparatus having a primary solenoid and one or more secondary solenoids which are energized in response to operation of the primary solenoid; said switching apparatus comprising a primary solenoid having a solenoid tube, a shiftable plunger slidably sustained in said tube, biasing means normally urging said plunger rearwardly to a retracted position, said plunger having a neck portion which is delineated by a pair of longitudinally spaced abutments, a flapper having a portion loosely embracing said neck portion between said abutments for movement with the plunger, said solenoid tube having a longitudinal passageway therein, said flapper having a portion projecting outwardly through said longitudinal passageway and thereby slidably keyed therein, said flapper normally residing in a rearwardly inclined inactive position resting against one of said abutments, the outer portion of the flapper travelling in an inactive longitudinal path during the forward power stroke of the plunger upon energization of said primary solenoid, said flapper pivoting to an active position by momentum force at a limit of said power stroke, said biasing means shifting said plunger rearwardly in a retracting stroke upon deenergization of said primary solenoid, said flapper resting against the second of said abutments in said forwardly inclined active position, the outer portion of the element travelling in a longitudinal path which is spaced outwardly from said inactive path during said retracting stroke, a normally open electrical contact device mounted in stationary position relative to the solenoid tube, said contact device including a yieldable actuating member residing adjacent said longitudinal passageway at an intermediate point along the longitudinal path of travel of said flapper, said actuating member residing in a plane spaced outwardly from said inactive path of travel and inwardly of said active path of travel, whereby the projecting portion of the flapper passes in spaced relation to said member during said power stroke and engages the member during the retracting stroke, said contact device being momentarily closed upon engagement of said actuating member, said contact device adapted to be electrically connected to one or more secondary solenoids to energize the same momentarily upon actuation of said member by the flapper.

References Cited in the file of this patent UNITED STATES PATENTS 1,352,889 Gallo et al. Sept. 14, 1920 2,263,051 Rittenhouse et al. Nov. 18, 1941 2,344,523 Stern Mar. 21, 1944 2,586,056 Kling et a1. Feb. 19, 1952 

